They will get into your filter and are big breeders its hard to get rid of them, if you live in a cold climate you could do it by removing the substrate into buckets along with any sponges (the young love hiding out in sponges) and placing everything outside during winter and let it freeze for a few days that should do it or boil everything. Do allot of reading before adding them once there in there in. some people don’t like them they only eat decaying plant matter and love algae. The smaller once will remove allot of algae from leaves there so tiny they can climb on the smallest leaves and get into every spot. You can also remove some manually at night after the lights go out just pick them off the glass.